This is an application for 1) a central computer, and 2) associated equipment to allow acquisition, manipulation, and display of anatomical data related to physiological studies on the vertebrate auditory system in the Eaton-Peabody Laboratory. Our scientific approach is to quantitatively trace signals through each stage of the auditory system; the signals studied are acoustic in the external, middle and inner ears, mechanoelectric and chemical in sensory cells, electrical in primary neurons and electrical and mechanical in centrifugal systems. The approach requires description of relevant anatomical structures, definition of the signals, and formulation of models for the physiological processes. As our physiological knowledge of signal behavior at the cellular level has improved, the need to relate this knowledge to anatomical knowledge at the same time has led to the development of a computer-aided anatomy (CAA) system whose applications and use are increasing rapidly. The Eaton-Peabody Laboratory (EPL) research team consists of personnel from four cooperating institutions in the Boston area. The EPL staff of more than 50 individuals includes acousticians, electrical engineers, biophysicists, anatomists, neurochemists, physiologists, psychologists, otolaryngologists and neurologists. Virtually all of the work is basic research, making use of pathological material when helpful. Although this group pioneered the use of computers in physiology, our research is now seriously hampered by an obsolete and inadequate central computer. In addition to the need to computerize our anatomical work, use of the computer for a variety of "routine" tasks (figure making, data processing, text processing) has added a rapidly growing additional load that is already difficult to handle with our present facilities. The addition of a VAX-11/750 central processor unit and peripheral equipment to computerize our anatomical studies will greatly enhance our efforts to understand the auditory system, a system that is of paramount importance for communication in humans and used in many different ways by vertebrates radiating into diverse ecological niches.